The most significant concerns in attaching a deck to a building are the use of improper or inadequate fasteners and that there is a risk that moisture may be trapped and accumulate at the point of attachment, thus creating conditions for decay and weakening of the materials at the point of attachment.
Improperly fastening the deck to the building can cause the deck to become unattached, thereby creating a danger for those persons on or around the deck. Some deck and balcony ledgers are only nailed to the house band joist, and this approach may not be adequate depending upon the span of the deck joists. As people gather on a deck, their weight and movement translate not just into a downward force but also into an outward force that acts as a lever prying the deck away from the house. Nails work well to resist the downward force but are inadequate for the outward force. Held in place only by the friction of bent wood fibers, nails tend to loosen when wood alternately shrinks and swells with changes in moisture content and temperature. Once nails loosen, they offer even less resistance to the prying forces of a crowd of people standing on the deck floor.
A screwed-in connector behaves differently. It gains increased frictional strength from the wedging action of wood fibers along the entire length of the shaft. A lag bolt, which looks like a giant screw, has as much as nine times the pullout resistance of a nail for every inch of penetration. Better still is the metal-to-metal connection of a true bolt, inserted in a drilled hole and fitted with a nut on the other side. Placing a washer on both sides spreads the pulling force over a larger portion of the beam. Both of these connectors offer an extra benefit over nails in that they don't suddenly pull out as wood shrinks and swells. But they may loosen over time, requiring periodic inspection and maintenance.
Also, if proper flashing is not installed, the wall sheathing and band joist can rot, destroying the original capacity of the nail connection. This could set up a situation where wood members of both the structure and deck are susceptible to rot. Accordingly, a number of prior art systems and methods have been developed to minimize the probability of trapping moisture at the point of attachment of a deck to a structure.
A common method of attaching a deck to a building is by installing roll flashing to the exterior of the structure. In new construction, the roll flashing is likely attached prior to the siding being attached. However, where a deck is to be attached to an existing structure, with attached siding, the siding should first be removed to expose the sheathing. After the roll flashing is attached, then a rim joist is attached over the roll flashing to the structure, preferably using lag bolts. The lag bolts will penetrate through the rim joist, flashing and sheathing and into a rim joist of the structure. Next, a window flashing is attached to the top of the attached rim joist to direct any moisture over the rim joist and away from the structure. Siding is then attached on top of the window flashing to complete the installation.
Although this is a common form of deck installation that has been used for many years, it is not without problems. Water can drip along or condense on the lag bolts, following the lag bolts to the inside of the house. This is especially problematic in climates that experience severe temperature swings between the summer and winter months. During the winter months, water can find its way behind the siding and alternatively thaw and freeze in response to temperature fluctuations, thus weakening the joint between the deck and the building.
In a typical home construction scenario, the house is built and sided before a deck or other accessory devices are attached to the house. Thus, in order to properly attach a deck to the house using methods described in prior art, the siding contractor will either need to leave part of the house without siding to allow the deck to be fastened thereto or already attached siding must be removed in order to properly attach the deck to the house. Both installation types add complexity and coordination problems to a construction project.
A number of prior patents disclose alternative methods of attaching a deck to a house. In U.S. Pat. No. 6,397,552 to Bourque, a deck attachment bracket and method of attaching a deck to a building is disclosed by use of an attachment bracket being mounted to the concrete foundation of an existing structure, preferably having a space between the structure and the deck. While Bourque's bracket and method may solve the problem of deteriorating and rotting wood joists, water may still find its way along the bolts into the concrete, allowing for its expansion and contraction in freezing and thawing weather, thereby weakening the hold of the bolts to the concrete. Thus, additional modification must be performed, such as caulking or otherwise sealing around the bolt holes, to prevent water from infiltrating the bolt holes.
In U.S. Pat. No. 6,311,449 to Morse, et al. discloses an “L” shaped bracket, the longer leg through which bolts are used to attach the bracket to the band board and joist of the house, the shorter leg through which bolts are used to attach to the band board of the house and ledger boards of the deck. As can be appreciated, this bracket and method does not solve the problem of water deteriorating the wood, thereby weakening the place of attachment.
Another example, U.S. Pat. No. 4,811,542 to Jewell discloses a deck bracket, which includes a wide flange and a narrow flange spaced apart from each other by a web. The deck bracket is then joined to the building, preferably by screws and the deck bolted to the deck bracket. The deck is thus spaced away from the building to reduce moisture accumulation. Jewell's method of construction however, includes placing the deck bracket adjacent to sheathing, caulking it and then protecting the area with siding, thus covering it. While the Jewell bracket does separate the deck structure from a building structure and thus reduces the possibility that moisture will be trapped between the two structures, it still requires siding modifications and caulking to prevent moisture draining down the siding of the structure thus accumulating and penetrating through the screw holes attaching the bracket to the structure.
Further, U.S. Pat. No. 5,201,156 to Newman also discloses a mounting bracket, which spaces a deck or the like away from the siding of a house or other like structure in order to prevent the accumulation of water at the joint. However, like the Bourque and Jewell brackets, Newman's bracket requires modifications to the exterior of a structure and/or caulking or the like in order to effectively waterproof the joint between the bracket and the house structure.
What is needed, therefore, is a deck attachment bracket and method that eliminates the joint between a deck and/or deck bracket and the exterior of a house or other structure, thereby eliminating any possibility that moisture could penetrate into the wooden house or other structure. What is further needed is an attaching means that will diminish or eliminate the reliance of the structural integrity solely upon the wooden members of the deck or attached structure. Preferably, such a bracket and attachment method should be adjustable to allow a single bracket design to be compatible with a variety of deck configurations and orientations.